1. SECTION 11.2 Areas of Parallelograms, Triangles, and Rhombuses

2. Heights of Parallelograms and Triangles The height MUST be an ALTITUDE!

3. PARALLELOGRAMS Area = base · height A = bh HINT: There is a special right triangle again!!!! 30 o 6

4. TRIANGLES Area = ½ base x height A = ½ bh Heights can be OUTSIDE the triangle!

5. TRIANGLES A = ½ bh Find the area of a triangle with sides 10,10, 8. 10 8 You need to find the height so ADD a line! 4 4 Use Pythagorean Theorem to find the height. 4 2 + h 2 = 10 2 16 + h 2 = 100 h 2 = 84

6. TRIANGLES A = ½ bh Find the area of an equilateral triangle with sides

7. RHOMBUS Area = half of the product of the diagonals A = ½ d 1 d 2

8. RHOMBUS A = ½ d 1 d 2 Another Special Right Triangle! They are everywhere! 60 o 9 9

9. SAT Problem. Find the base length of a triangle with an area of 52 cm 2 and a height of 13 cm. a)2 cm b)4 cm c)8 cm d)16 cm e)26 cm 13 cm A = ½ bh 52 = ½ b(13) 52 = 6.5b 8 = b

10. Practice Page 431 WRITTEN EXERCISES #2-20 EVENS, draw pictures!!!!!